Polarity manipulation in polystyrene for enhanced bio-polymer miscibility

ABSTRACT

A styrenic composition including a polar modified styrenic co-polymer resulting from the polymerization of a combined mixture of at least one styrenic monomer and at least one comonomer and a biodegradable component is disclosed. The at least one comonomer includes a polar functional group and the polar modified styrenic co-polymer and the biodegradable component are combined to obtain a styrenic composition having a biodegradable component. Also disclosed is a method of enhancing bio-polymer miscibility in a styrenic based polymer. The polarity of a blend is manipulated by combining a styrenic monomer and a polar co-monomer to form a combined mixture and subjecting the combined mixture to polymerization to obtain a styrenic polymer blend to which a bio-polymer is added.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/171,828, filed on Jun. 29, 2011.

FIELD

The present invention is generally related to polymeric compositions.More specifically, the present invention is related to polystyreneblends containing biodegradable polymer compositions.

BACKGROUND

Styrene, also known, as vinyl benzene, is an aromatic compound that isproduced in industrial quantities from ethyl benzene. The most commonmethod of styrene production comprises the dehydrogenation of ethylbenzene, which produces a crude product of styrene and unreacted ethylbenzene and hydrogen. Polystyrene is an aromatic polymer produced fromstyrene monomer. Polystyrene is a widely used polymer commonly found inmany commercial applications.

Many industries seek to replace the metals used for structural materialswith plastics. Plastics like polystyrene are typically lighter and lessexpensive than metals. Plastics may also be used as thermal orelectrical insulators because they do not typically interfere withmagnetic or electrical signals. Polystyrene is a durable and inexpensivepolymer that is frequently encountered in daily life. However,polystyrene is typically weaker than metals. Thus, polystyrene iscommonly combined with other polymers or composite materials such asfibers to provide improved strength and other properties. Some of thevaried applications of polystyrene include insulation, foam cups,disposable cutlery, food packaging, office supplies, CD/DVD cases,housewares, appliance linings, cosmetics packaging, toys, computerhousings, bottles, tubing, and dunnage.

Polystyrene containing products are often discarded and only a smallfraction of discarded polystyrene products are recovered and recycled.In addition, byproducts and excess amounts of polystyrene andpolystyrene containing compositions are produced during the process ofmolding, shaping and producing the products containing polystyrene.These byproducts, along with post consumer polystyrene products, oftenbecome waste. This waste typically ends up in landfills, orincinerators, or sometimes results in litter. Most of these products arenon-biodegradable and thus remain long after disposal.

Poly(lactic acid) or PLA is a bio-derived and biodegradable andcompostable polymer. Use of PLA as a biodegradable modifier topolystyrene brings additional marketable “environmentally friendly”value to commodity polystyrene and can add a biodegradable aspect to theotherwise non-biodegradable commodity polystyrene. However, combiningthese two materials has proven to be difficult. PLA and polystyrene forman immiscible polymer blend when combined, therefore, the combination ofthe two materials into one homogenous phase has been difficult. Theseheterogeneous mixtures of polystyrene and PLA have not resulted inproducts that can replace stronger, non-biodegradable, polystyreneblends currently on the market.

It would thus be desirable to obtain a homogenous polystyrene blendcontaining PLA. It would also be desirable to obtain a biodegradablepolystyrene blend that is strong enough to be used in a wide variety ofapplications.

SUMMARY

An embodiment of the present invention, either by itself or incombination with other embodiments of the invention, includes a styrenicbased polymer containing a biodegradable component and to an articlemade from the styrenic based polymer containing a biodegradablecomponent.

An embodiment of the invention is a styrenic composition that includes apolar modified styrenic co-polymer resulting from the polymerization ofa combined mixture of at least one styrenic monomer and at least onecomonomer that includes includes a polar functional group. The polarmodified styrenic co-polymer and a biodegradable component are combinedto obtain a styrenic composition comprising a biodegradable componentand a biodegradable component.

The styrenic monomer can be selected from the group consisting ofstyrene, alpha-methyl styrene, vinyl toluene, p-methyl styrene, t-butylstyrene, o-chlorostyrene, and vinyl pyridine and any combinationsthereof. The styrenic co-polymer can be present in the polar modifiedblend in amounts ranging from 75 to 99 wt % based on the total weight ofthe polar modified blend.

The comonomer having a polar functional group can be selected from thegroup of alkyl-(meth)acrylate, hydroxyl-alkyl(meth)acrylate,caprolactone(meth)acrylate, polyethylene glycol(meth)acrylate,silyl-(meth)acrylate, and fluoro-alkyl(meth)acrylate.

The biodegradable component can be selected from the group consisting ofpolylactic acid (PLA), biodegradable polyesters, polyhydroxybutyrates(PHB), polyhydroxyalkanoates (PHA), polycaprolactone (PCL), polyvinylalcohol (PVA), and combinations thereof. The biodegradable component inthe styrenic based polymer can have a particle size distribution with apeak particle size of less than 2.0 μm.

A polar additive can be present in the polar modified blend in amountsranging from 0.5 to 10 wt % based on the total weight of the blend, andcan be a polar plasticizer. The polar plasticizer can be selected fromthe group of styrene-maleic anhydride, glyceride oil, oligomericpolyether and polyester, and combinations thereof.

An embodiment of the present invention, either by itself or incombination with other embodiments of the invention, is a method ofmaking a styrenic polymer containing a biodegradable component bycombining a styrenic monomer and a monomer comprising a polar functionalgroup to form a combined mixture. The combined mixture is polymerized toform a polar modified styrenic co-polymer that is combined with abiodegradable component to obtain a styrenic based polymer containing abiodegradable component.

In an embodiment of the present invention, either by itself or incombination with other embodiments of the invention, the method caninclude combining the styrenic co-polymer with a polar additive prior tocombining the polar modified styrenic co-polymer with the biodegradablecomponent.

The embodiments disclosed herein are usable and combinable with everyother embodiment disclosed herein, and consequently, this disclosure isenabling for any and all combinations of the embodiments disclosedherein.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a graph illustrating PLA particle size distribution fromblends of PLA with various polystyrene copolymers.

FIG. 2 is a graph illustrating PLA particle size distribution fromblends of PLA with polystyrene modified with SMAs.

FIG. 3 is a graph illustrating PLA particle size distribution fromblends of PLA in plasticized HEMA-modified polystyrene.

FIG. 4 is a graph illustrating solvent intake in HEMA-modifiedpolystyrene.

FIG. 5 is a graph illustrating the PLA particle size distribution inHEMA-modified polystyrene.

FIG. 6 is a graph illustrating the glass transition temperature of PEGmodified polystyrene and HEMA-modified polystyrene.

FIG. 7 is a graph illustrating PLA particle size distribution ofHEMA-modified polystyrene and PEG modified polystyrene.

FIG. 8 is a graph illustrating PLA particle size distribution ofHEMA-modified polystyrene and Caprolactone modified polystyrene and anunmodified polystyrene reference.

DETAILED DESCRIPTION

The present invention includes blends of styrenic polymers with optionalpolar additives and a biodegradable component. In an embodiment, thepresent invention includes blends of polystyrenic homopolymers and/orcopolymers and polar additives to enhance the miscibility ofbiodegradable components. In another embodiment, the present inventionincludes a blend of homopolymers and/or copolymers of polystyrene withpolar additives and with biodegradable components. The present inventionalso includes blends of styrenic polymers and biodegradable polymers. Ina more specific embodiment, the present invention includes a blend ofhomopolymers and/or copolymers of polystyrene and poly(lactic acid), orPLA, based homopolymers and/or copolymers.

In an embodiment, the blend of the presently disclosed compositionincludes a styrenic polymer. In another embodiment, the styrenic polymerincludes polymers of monovinylaromatic compounds, such as styrene,α-methyl styrene and ring-substituted styrenes. In an alternativeembodiment, the styrenic polymer includes a homopolymer and/or copolymerof polystyrene. In a further embodiment, the styrenic polymer ispolystyrene. In an even further embodiment, styrenic monomers for use inthe styrenic polymer composition can be selected from the group ofstyrene, alpha-methyl styrene, vinyl toluene, p-methyl styrene, t-butylstyrene, o-chlorostyrene, vinyl pyridine, and any combinations thereof.The styrenic polymeric component in the blend of the present inventioncan be produced by any known process. In an embodiment, the styrenicpolymer is polystyrene.

The blend of the present invention may contain any desired amounts of astyrenic polymer. In an embodiment, the blend contains at least 50 wt %of a styrenic polymer. In another embodiment, the blend contains astyrenic polymer in amounts ranging from 1 to 99 wt %, 50 to 95 wt %, 60to 92 wt %, and optionally 75 to 90 wt %. In a further embodiment, theblend contains a styrene polymer in amounts ranging from 80 to 99 wt %.In an even further embodiment, the blend contains a styrenic polymer inamounts ranging from 90 to 95 wt %.

In embodiments of the present invention the styrenic polymer of thepresent invention may include general-purpose polystyrene (GPPS),high-impact polystyrene (HIPS), or any combinations of the two. In anembodiment, the styrenic polymer of the present invention may be HIPSthat further contains an elastomeric material. In an embodiment, theHIPS may contain an elastomeric phase embedded in the polystyrenematrix, which results in the styrenic polymer having an increased impactresistance.

The HIPS may contain any desired elastomeric material. In an embodiment,the elastomeric material is a conjugated diene monomer. In anembodiment, the conjugated diene monomers may include without limitation1,3-butadiene, 2-methyl-1,3-butadiene, 2-chloro-1,3 butadiene,2-methyl-1,3-butadiene, and 2-chloro-1,3-butadiene. In anotherembodiment, the elastomer is an aliphatic conjugated diene monomer. Inan embodiment, the aliphatic conjugated diene monomers include C₄ to C₉dienes such as butadiene monomers. Blends or copolymers of the dienemonomers may also be used as well as mixtures or blends of one or moreelastomers. In an embodiment, the elastomer includes a homopolymer of adiene monomer. In another embodiment, the elastomer includespolybutadiene. The elastomer may be present in the HIPS in any desiredamounts. In an embodiment, the elastomer may be present in the HIPS inamounts ranging from 1 to 20 wt. %, alternatively from 2 to 15 wt. %,and alternatively 5 to 11 wt. % based on the total weight of the HIPS.

The styrenic polymer of the present invention may be a styreniccopolymer. The styrenic polymer of the present invention may be formedby co-polymerizing a first monomer with a second monomer. The firstmonomer and the second monomer may be co-polymerized by having the firstmonomer and the second monomer present in a reaction mixture that issubjected to polymerization conditions. The first monomer may includemonovinylaromatic compounds, such as styrene, alpha-methyl styrene andring-substituted styrenes. In an embodiment, the first monomer isselected from the group of styrene, alpha-methyl styrene, vinyl toluene,p-methyl styrene, t-butyl styrene, o-chlorostyrene, vinyl pyridine, andany combinations thereof. In another embodiment, styrene is usedexclusively as the first monomer.

The first monomer may be present in the reaction mixture in any desiredamounts. In an embodiment, the first monomer is present in the reactionmixture in amounts of at least 50 wt % of the reaction mixture. Inanother embodiment, the first monomer is present in the reaction mixturein amounts ranging from 90 to 99.9 wt % of the reaction mixture. In afurther embodiment, the first monomer is present in the reaction mixturein amounts ranging from 95 to 99 wt %.

The second monomer may contain a polar functional group. In anembodiment, the second monomer containing a polar functional group is apolar vinyl functional monomer. In another embodiment, the polar vinylfunctional monomer is selected from the group of alkyl-(meth)acrylate,hydroxyl-alkyl(meth)acrylate, caprolactone(meth)acrylate, polyethyleneglycol(meth)acrylate, silyl-(meth)acrylate, andfluoro-alkyl(meth)acrylate.

The styrenic polymer may be prepared from any desired amounts of asecond monomer. In an embodiment, the second monomer is present in thereaction mixture in amounts of at least 0.1 wt %. In another embodiment,the second monomer is present in the reaction mixture in amounts rangingfrom 1 to 20 wt %. In a further embodiment, the second monomer ispresent in the reaction mixture in amounts ranging from 1 to 10 wt %. Inan even further embodiment, the second monomer is present in thereaction mixture in amounts ranging from 1 to 5 wt %.

In addition to a styrenic polymer component and a biodegradablecomponent, the blend of the present invention may also contain polaradditives.

The polar additives of the present invention may contain polarplasticizers. In an embodiment, the polar plasticizers are selected fromthe group of styrene-maleic anhydride, glyceride oil, oligomericpolyether and polyester, and combinations thereof. In an embodiment, thestyrene-maleic anhydride (SMA) polymers include SMA® EF40 (EF40) andSMA® EF80 (EF80), which are commercially available from SartomerCompany, Inc. EF40 includes styrene-to-maleic anhydride ratios of 4:1,while EF 80 includes styrene-to-maleic anhydride ratios of 8:1. In anembodiment the styrene-to-maleic anhydride ratios of can range from 1:1to 12:1, optionally from 2:1 to 11:1, optionally from 4:1 to 10:1. In anembodiment, the polar plasticizer(s) may be present in the blend inamounts of at least 0.1 wt % based on the total weight of the blend. Inanother embodiment, the polar plasticizer(s) may be present in the blendin amounts ranging from 0.5 to 10 wt %. In a further embodiment, thepolar plasticizer(s) may be present in the blend in amounts ranging from1 to 5 wt %. In an even further embodiment, the polar plasticizer(s) maybe present in the blend in amounts ranging from 1.5 to 2.5 wt %.

The blends of the present invention may contain any bio-polymercontaining component. In an embodiment, the bio-polymer is abiodegradable polymer. In another embodiment, the blends of the presentinvention may contain any biodegradable polymer or polymers. In anotherembodiment, the blends of the present invention may contain any polarbio-polymer. In another embodiment, the bio-polymer and thebiodegradable polymer are each selected from the group of polylacticacid (PLA), polyhydroxybutyrates (PHB), polyhydroxyalkanoates (PHA),polycaprolactone (PCL), polyvinyl alcohol (PVA), and combinationsthereof. In a further embodiment, the biodegradable polymer and thebio-polymer are each selected from the group of polylactic acid (PLA),polyhydroxybutyrates (PHB), polyhydroxyalkanoates (PHA),polycaprolactone (PCL), polyvinyl alcohol (PVA), polybutylenesuccinatehomopolymer, polybutyleneadipate homopolymer,polybutylenesuccinate-adipate copolymer, polyethylenesuccinatehomopolymer, polyethyleneadipate homopolymer,polyethylenesuccinate-adipate copolymer, and a copolyester of analiphatic polyester, and combinations thereof. In a further embodiment,the biodegradable polymer and the bio-polymer are each selected from apolysaccharide such as starch, cellulose, and glycogen and othersugar-based polymers.

In an embodiment, the biodegradable polymer is polylactic acid.Poly(lactic acid), polylactic acid, or PLA, can be made from lactic acid(lactate). Lactic acid is a naturally occurring molecule that is widelyused in foods as a preservative and flavoring agent. Lactic acid may bechemically synthesized or produced by microbial fermentation of sugarssuch as glucose or hexose. In an embodiment, lactic acid is produced byfermentation of sugar feed stocks. The sugar feed stocks may be obtainedfrom farm products, farming by-products and wastes. The sugar feedstocks may be obtained from farm products, farming by-products andwastes. In another embodiment, the sugar feed stocks are selected fromthe group of potato wastes, corn products, beet products, sugar canewastes, and dairy wastes and combinations thereof. In an embodiment, thelactic acid produced by fermentation of sugar feed stocks issubsequently converted to obtain lactic acid monomers, which are thenpolymerized to obtain PLA.

Lactic acid monomers essentially exists in two stereoisomeric formswhich yield morphologically distinct polymers selected from the group ofpoly(L-lactic acid), poly(D-lactic acid), poly(D,L-lactic acid), andmeso-polylactic acids and any combinations thereof. PLA can includehomopolymers and/or copolymers of lactic acid. The homopolymers oflactic acid can be selected from the group of poly(L-lactic acid),poly(D-lactic acid), and poly(D,L-lactic acid) and any combinationsthereof. The copolymers of lactic acid may have a lactic acid comonomercontent of at least 50 wt % based on the total weight of the copolymer.The copolymers of lactic acid may have a lactic acid comonomer contentthat ranges from 50 to 100 wt %, optionally from 60 to 95 wt %,optionally from 70 to 90 wt % based on the total weight of thecopolymer.

Lactic acid cannot be directly polymerized to a useful product, instead,lactic acid is optionally oligomerized and catalytically dimerized tomake a cyclic lactide monomer (lactic acid monomer). Althoughdimerization also generates water, it can be separated prior topolymerization. The polymerization may be performed by polycondensationmethods or ring-opening polymerization methods. In an embodiment, PLAmay be produced by polycondensation. In an embodiment in which thepolymerization is performed by polycondensation, the lactic acid monomermay be directly subjected to dehydropolycondensation to obtain a desiredpolylactic acid composition. In the direct dehydration polycondensationmethod, the lactic acid may be subjected to azeotropic dehydrationcondensation in the presence of an organic solvent.

In an embodiment, the PLA may be produced by ring-openingpolymerization. In ring-opening polymerization, lactide (i.e., cyclicdimer of lactic acid) may be subjected to polymerization by the aid of apolymerization-adjusting agent and a catalyst to obtain polylactic acid.

The polylactic acid may have a weight average molecular weight rangingfrom 5,000 to 1,000,000, 10,000 to 400,000, 30,000 to 300,000, andoptionally 100,000 to 250,000. In an embodiment, the polylactic acid caninclude commercially available polylactic acids such as those sold byNatureWorks LLC (owned by Cargill Corporation), including Ingeo PLA3251D, NatureWorks PLA 4032, 4042, and 4060 trade names. The PLA 4032grade may have a D isomer monomer content from 1.2 to 1.6 wt %, the PLA4042 grade may have a D isomer monomer content from 3.7 to 4.8 wt %, andthe PLA 4060 grade may have a D isomer monomer content from 11.0 to 13.0wt %. In a non-limiting embodiment the polylactic acid can have a Disomer monomer content from 0.5 to 30.0 wt %, optionally from 1.0 to25.0 wt %, optionally from 1.0 to 20.0 wt %, optionally from 1.0 to 15.0wt %.

The blend of the presently disclosed composition may contain any amountof PLA in order to achieve desired properties. In an embodiment, theblend contains at least 0.1 wt % PLA. In another embodiment, the blendcontains amounts ranging from 0.1 to 90 wt %, 0.5 to 50 wt %, 1 to 30 wt%, 2 to 20 wt %, 3 to 10 wt %, and optionally 5 wt % PLA. In a furtherembodiment, the blend contains PLA in amounts ranging from 1 to 10 wt %PLA. In an even further embodiment, the blend contains PLA in amountsranging from 3 to 8 wt % PLA.

The blend of the presently disclosed composition may be prepared byco-polymerizing a styrenic monomer with a second monomer containing apolar functional group. In an embodiment, styrene monomer and the secondmonomer containing the polar functional group are combined andpolymerized in a polymerization reactor wherein the styrene monomer andsecond monomer containing the polar functional group are copolymerizedto produce a polystyrene copolymer. The polystyrene copolymer may thenbe mixed with a biodegradable polymer to obtain a biodegradablepolymeric blend. The biodegradable polymeric blend may then be sent toan extruder or other step to obtain an end use article.

The polymerization of the styrenic monomer and the second monomer, orco-monomer, may be carried out using any method known to one havingordinary skill in the art of performing such polymerizations. In anembodiment, the polymerization may be carried out by using apolymerization initiator.

In an embodiment, the polymerization initiators include radicalpolymerization initiators. These radical polymerization initiatorsinclude but are not limited to perketals, hydroperoxides,peroxycarbonates and the like. In another embodiment, the polymerizationinitiators may be selected from the group of benzoyl peroxide, lauroylperoxide, t-butyl peroxybenzoate, and1,1-di-t-butylperoxy-2,4-di-t-butylcycleohexane, and combinationsthereof. In an embodiment, the amount of the polymerization initiator isfrom 0 to 1 percent by weight of the monomers and co-monomers. Inanother embodiment, the amount of the polymerization initiator is from0.01 to 0.5 percent by weight of the monomers and co-monomers. In afurther embodiment, the amount of the polymerization initiator is from0.025 to 0.05 percent by weight of the monomers and co-monomers.

Any process capable of processing or polymerizing styrenic monomers maybe used to prepare the styrenic co-polymer of the presently disclosedcomposition. In an embodiment, any polymerization reaction for preparinggeneral purpose polystyrene or high-impact polystyrene may be used toprepare the styrenic co-polymer of the presently disclosed composition.In an embodiment, the polymerization reaction to prepare the styrenicco-polymer may be carried out in a solution or mass polymerizationprocess. Mass polymerization, or bulk polymerization, refers to thepolymerization of a monomer in the absence of any medium other than themonomer and a catalyst or polymerization initiator. Solutionpolymerization refers to a polymerization process wherein the monomersand polymerization initiators are dissolved in a non-monomeric liquidsolvent at the beginning of the polymerization reaction.

The polymerization may be either a batch process or a continuousprocess. In an embodiment, the polymerization reaction may be carriedout using a continuous production process in a polymerization apparatusincluding a single reactor or multiple reactors. The styrenic polymercomposition can be prepared using an upflow reactor, a downflow reactor,or any combinations thereof. The reactors and conditions for theproduction of a polymer composition, specifically polystyrene, aredisclosed in U.S. Pat. No. 4,777,210, which is incorporated by referenceherein in its entirety.

The temperature ranges useful in the polymerization process of thepresent disclosure can be selected to be consistent with the operationalcharacteristics of the equipment used to perform the polymerization. Inan embodiment, the polymerization temperature ranges from 90 to 240° C.In another embodiment, the polymerization temperature ranges from 100 to180° C. In yet another embodiment, the polymerization reaction may becarried out in multiple reactors in which each reactor is operated underan optimum temperature range. For example, the polymerization reactionmay be carried out in a reactor system employing a first polymerizationreactor and a second polymerization reactor that may be eithercontinuously stirred tank reactors (CSTR) or plug-flow reactors. In anembodiment, a polymerization process for the production of a styrenicco-polymer of the type disclosed herein containing multiple reactors mayhave the first reactor (e.g., a CSTR), also referred to as aprepolymerization reactor, operated under temperatures ranging from 90to 135° C. while the second reactor (e.g. CSTR or plug flow) may beoperated under temperatures ranging from 100 to 165° C.

In an alternative embodiment, the co-polymer may be obtained bypolymerization in which heat is used as the initiator. In a furtherembodiment, the co-polymer may be prepared using a non-conventionalinitiator such as a metallocene catalyst as is disclosed in U.S. Pat.No. 6,706,827 to Lyu, et al., which is incorporated herein in itsentirety by reference. In one embodiment, the monomers may be admixedwith a solvent and then polymerized. In another embodiment, one of themonomers is dissolved in the other and then polymerized. In stillanother embodiment, the monomers may be fed concurrently or separatelyto a reactor, either neat or dissolved in a solvent, such as mineraloil. In yet another embodiment, the second monomer may be preparedin-situ or immediately prior to the polymerization by admixing the rawmaterial components, such as an unsaturated acid or anhydride and ametal alkoxide, in-line or in the reactor. Any process for polymerizingmonomers having polymerizable unsaturation known to be useful to thoseof ordinary skill in the art in preparing such polymers may be used. Forexample, the process disclosed in U.S. Pat. No. 5,540,813 to Sosa, etal., may be used and is incorporated herein in its entirety byreference. The processes disclosed in U.S. Pat. No. 3,660,535 to Finch,et al., and U.S. Pat. No. 3,658,946 to Bronstert, et al., may be usedand are both incorporated by reference herein in their entirety. Anyprocess for preparing general purpose polystyrene may be used to preparethe styrenic co-polymer of the presently disclosed composition.

In certain embodiments, the styrenic copolymer may be admixed withadditives prior to being used in end use applications. For example, thestyrenic copolymer may be admixed with additives that include withoutlimitation stabilizers, chain transfer agents, antioxidants, UVstabilizers, lubricants, plasticizers, ultra-violet screening agents,oxidants, anti-oxidants, anti-static agents, ultraviolet lightabsorbents, fire retardants, processing oils, mold release agents,fillers, pigments/dyes, coloring agents, and other similar compositions.Any additive known to those of ordinary skill in the art to be useful inthe preparation of styrenic copolymers may be used.

In an embodiment, styrene monomer is combined with a polar functionalcomonomer and subsequently polymerized to form a polar polystyrenecopolymer. The polar polystyrene copolymer can then be combined with PLAto obtain a blend.

In an embodiment, styrene monomer is combined with a polar functionalcomonomer and subsequently polymerized to form a polar polystyrenecopolymer. The polar polystyrene copolymer can then be combined withpolystyrene and a biodegradable polymer to obtain a blend. In anotherembodiment, the polystyrene is selected from general purpose polystyrene(GPPS) and high impact polystyrene (HIPS) and combinations thereof.

In an embodiment, styrene monomer is combined with a second monomer andsubsequently polymerized to form a polystyrene copolymer. Thepolystyrene copolymer may then be combined with at least one polaradditive and a biodegradable polymer to form a blend. In an embodiment,the polystyrene copolymer is first mixed with at least one polaradditive and then mixed with biodegradable polymer to obtain a blend. Inanother embodiment, the polystyrene copolymer is first mixed withbiodegradable polymer and then mixed with at least one polar additive toobtain a blend. In a further embodiment, the polystyrene copolymer issimultaneously combined with biodegradable polymer and at least onepolar additive to obtain a blend. The final blend may then be sent to anextruder or other step to obtain an end use article.

In an embodiment, styrene monomer is combined with a polar comonomer anda plasticizer and subsequently polymerized to form a polar polystyrenecopolymer. The polar polystyrene copolymer can then be combined with abiodegradable polymer to obtain a blend.

The styrenic copolymer of the presently disclosed composition may haveany desired molecular weight that enhances the polarity distributionthat may improve the dispersion of biodegradable polymers when comparedto general purpose polystyrene. In an embodiment, the styrenic copolymerof the presently disclosed composition may have a number averagemolecular weight (Mn) ranging from 40,000 g/mol to 10,000,000 g/mol. Inanother embodiment, the styrenic copolymer has an Mn ranging from 50,000to 200,000 g/mol. In a further embodiment, the styrenic copolymer has anMn ranging from 75,000 to 150,000 g/mol. The styrenic copolymer may havea weight average molecular weight (Mw) ranging from 100,000 g/mol to10,000,000 g/mol. In another embodiment, the styrenic copolymer has anMw ranging from 200,000 to 500,000 g/mol. In a further embodiment, thestyrenic copolymer has an Mw ranging from 250,000 to 400,000 g/mol. Thestyrenic copolymer may have a z-average molecular weight (Mz) rangingfrom 200,000 g/mol to 10,000,000 g/mol. In another embodiment, thestyrenic copolymer has an Mz ranging from 300,000 to 800,000 g/mol. In afurther embodiment, the styrenic copolymer has an Mz ranging from400,000 to 550,000 g/mol.

In an embodiment, the blend has a polydispersity index (PDI) (Mw/Mn)ranging from 1.0 to 5.0. In another embodiment, the blend has apolydispersity index ranging from 1.5 to 3.0. In a further embodiment,the blend has a polydispersity index ranging from 2.0 to 2.5.

In an embodiment, the composition of the presently disclosed compositionhas a melt flow index (MFI), or melt flow rate (MFR), of at least 1.0g/10 min. as determined in accordance with ASTM D-1238. In anotherembodiment, the composition has a melt flow rate (MFR) ranging from 2.0g/10 min to 30.0 g/10 min. In an alternative embodiment, the compositionhas a MFR ranging from 1.5 to 5.0 g/10 min. In another alternativeembodiment, the composition has a MFR ranging from 1.5 to 3.0 g/10 min.In a further embodiment, the composition has a MFR ranging from 2.0 to2.5 g/10 min.

In an embodiment, the composition has a glass transition temperature(Tg) ranging from 50 to 200° C. In another embodiment, the compositionhas a Tg ranging from 75 to 150° C. In a further embodiment, thecomposition has a Tg ranging from 80 to 110° C. In an even furtherembodiment, the composition has a Tg ranging from 85 to 103° C.

In an embodiment, the blend of the presently disclosed composition hasan average particle size (phase domain size) distribution, defined as(D90-D10)/D50), ranging from 0.1 to 1000. In the equation,(D90-D10)/D50), D90, D10, and D50 represent diameters at which 90%, 10%,and 50% of particles are smaller than, respectively. In anotherembodiment, the blend has an average particle size distribution rangingfrom 10 to 1000.

In a further embodiment, the blend has a particle size distributionhaving a peak particle size ranging from 30 to 300 μm. In an alternativeembodiment, the blend has a particle size distribution having a peakparticle size ranging from 0.3 to 3 μm. In another alternativeembodiment, the blend has a particle size distribution having a peakparticle size ranging from 2 to 10 μm.

In an embodiment, the blend of the presently disclosed composition hasan average particle size ranging from 0.3 to 30 μm. In anotherembodiment, the blend has an average particle size ranging from 1 to 15μm. In a further embodiment, the blend has an average particle sizeranging from 2 to 8 μm.

An end use article may include a blend of the presently disclosedcomposition. In an embodiment, the articles include films, sheets andthermoformed or foamed articles. For example, a final article may bethermoformed from a sheet containing the blend. In an embodiment, anarticle can be obtained by subjecting the polymeric composition to aplastics shaping process such as blow molding, extrusion, injection blowmolding, injection stretch blow molding, thermoforming, and the like.The polymeric composition may be formed into end use articles includingfood packaging, office supplies, plastic lumber, replacement lumber,patio decking, structural supports, laminate flooring compositions,polymeric foam substrate, decorative surfaces, outdoor furniture,point-of-purchase signs and displays, house wares and consumer goods,building insulation, cosmetics packaging, outdoor replacement materials,lids and food/beverage containers, appliances, utensils, electroniccomponents, automotive parts, enclosures, protective head gear, medicalsupplies, toys, golf clubs and accessories, piping, business machinesand telephone components, shower heads, door handles, faucet handles,and the like.

EXAMPLES Example 1

A series of polystyrene samples were made with the addition of polarmodifiers as co-monomers or additives as listed in Table 1. The polarmodifiers listed include styrene-maleic anhydride (SMA) used asadditives, including SMA® 1000P, SMA® 3000P, and SMA® EF80, which areall commercially available from Sartomer Company, Inc. The polarmodifiers listed in Table 1 also include butyl acrylate, butylmethacrylate, hydroxyethylmethacrylate (HEMA), and maleic anhydride(MAH), which were used as co-monomers. In Table 1, PDI representspolydispersity index, Tg₁ represents the first glass transitiontemperature and Tg₂ represents a second glass transition temperature, ifapplicable.

TABLE 1 Characterization of Modified Polystyrene Modifier SMA 1000P SMA3000P None (1:1) (3:1) SMA EF80 (8:1) wt % 0 5.0 5.0 5.0 mol (# of moles0 0.025 0.012 0.005 of polar monomer unit)/(100 g of polymer)Transparency Clear Opaque Opaque Opaque Tg₁ 105.2 104.8 104.5 104.4 Tg₂n/a 169.3 n/a n/a Melt Flow Rate 2.1 2.2 2.8 2.9 Mn 130,000 138,000132,000 84,100 Mw 271,000 273,000 269,000 262,000 Mz 415,000 439,000418,000 417,000 PDI 2.1 2.0 2.0 3.1 Peak MW 259,000 255,000 259,000265,000 Modifier Butyl Butyl Acrylate Methacrylate HEMA MAH MAH wt % 5.05.0 5.0 1.75 3.5 mol (# of moles 0.039 0.035 0.038 0.018 0.036 of polarmonomer unit)/(100 g of polymer) Transparency Clear Clear Clear ClearSemi-clear Tg₁ 94.8 98.2 102.6 105.0 104.0 Tg₂ n/a n/a n/a n/a n/a MeltFlow Rate 3.3 2.9 1.7 2.2 3.3 Mn 136,000 122,000 128,000 115,000 97,300Mw 184,000 260,000 312,000 250,000 220,000 Mz 433,000 398,000 529,000391,000 350,000 PDI 2.1 2.1 2.4 2.2 2.3 Peak MW 271,000 250,000 270,000239,000 212,000

An indicator of polarity change in polystyrene is how well the materialblends with another polar polymer such as polylactic acid (PLA). In thisexample, the modified polystyrene samples above were blended with 5 wt %PLA in a mixer. The mixer was operated under a temperature of 210° C.under a nitrogen atmosphere for 3 minutes with agitation under speeds of60 rpm. The resulting blends were opaque. The size of PLA particles inthe blends was evaluated by dynamic light scattering. The blend sampleswere dispersed in methyl ethyl ketone (MEK), a good solvent forpolystyrene but not for PLA. FIG. 1 and FIG. 2 show the PLA particlesize distribution from different polystyrene blends. FIG. 1 comparespolystyrene copolymerized with different comonomers. All of thepolystyrene copolymer samples showed increased dispersion of PLA whencompared to crystal polystyrene. Incorporation of HEMA showed a narrowerdistribution peaked at particle sizes of 0.5 μm. Similar results wereobtained with polystyrene modified by butyl-acrylate/methacrylates aswell as maleic anhydride. Appearances of multiple maxima (or peaks) at10 to 100 μm indicated a significant presence of large PLA domains inthose blends.

FIG. 2 compares polystyrene modified with different styrene-maleicanhydride copolymers (SMAs). The SMAs were incorporated into polystyreneduring batch reactions as a way of physical blending. The PLA particlesize distributions from the SMA blends did not demonstrate a noticeabledecrease when compared to GPPS. Wider PLA particle size distributionswere observed in the SMA blends compared with polystyrene modifiedthrough copolymerization with polar comonomers. The SMAs were not aseffective as polar comonomers due to the relatively lower molarconcentration of polar groups of SMAs under the same weight percentageloading (see Table 1 above). In addition, the SMAs containing the higherpercentage of maleic anhydride (such as 1000P and 3000P) were lesssoluble in styrene. A miscible blend of GPPS and SMA was only made withSMA EF80, which had a styrene-to-maleic anhydride of 8:1 and containedthe lowest concentration of maleic anhydride among the various SMAsused.

Example 2

In a second example, seven modified polystyrene samples were polymerizedand analyzed. For each sample, 2.5 wt % of HEMA was added as acomonomer, based on the total weight of the feed to be polymerized. Alsofor each sample, the polarity in polystyrene was further enhancedthrough the physical addition of certain polar additives. Each samplewas characterized in terms of molecular weight, melt flow index andthermal behavior, as listed in Table 2. The type of polar additive usedvaried in each sample. In the first sample, no polar additive was used,while six different polar additives were used in the remaining samples.The five polar additives were styrene maleic anhydride (SMA), includingstyrene-to-maleic anhydride ratios of 4:1 (SMA EF40) and 8:1 (SMA EF80),poly(1,4-butlyene adipate) (Adipate), epoxidized linseed oil (Vikoflex®7190, commercially produced by Arkema, Inc.) (V7190), polyethyleneglycol (PEG400), and polyethylene glycol (PEG1000).

TABLE 2 Molecular Weights, Melt Index and Glass Transition Temperatureof Modified Polystyrene. Tg Mn of Additive Mn Mw Mz Mp PDI MFI (° C.)Plasticizer None 142000 336000 523000 315000 2.4 1.9 103.2 + EF40 104000338000 675000 253000 3.3 1.1 103.7 4500 EF80 97000 299000 534000 2600003.1 2.1 103.2 7500 Adipate 132000 282000 438000 267000 2.1 3.8 95.9 1000V7190 122000 264000 414000 247000 2.2 4.0 89.7 878 PEG400 120000 261000405000 247000 2.2 4.7 87.6 400 PEG1000 115000 265000 424000 286000 2.33.9 87.4 1000

These polystyrene samples were then blended with polylactic acid (PLA).An indirect indicator of polarity change in polystyrene is how well thematerial blends with another polar polymer such as PLA. The polaritychange of the modified polystyrene was evaluated by physically blendingthe plasticized polystyrene with 5 wt % PLA Ingeo™ 3251D, commerciallyavailable from NatureWorks LLC, in a Haake mixer. The mixer was operatedunder a temperature of 210° C. under a nitrogen atmosphere for 3 minuteswith agitation under speeds of 60 rpm. The PLA domain size inpolystyrene was characterized by dynamic light scattering in methylethyl ketone (MEK), which is a good solvent for polystyrene but not forPLA. The results in FIG. 3 show that the PLA blend with HEMA onlymodified polystyene has a PLA domain size of about 0.8˜0.9 μm. UsingHEMA only modified polystyene as a reference, the size of the PLA domainwas further reduced when the polymer was modified with epoxidizedlinseed oil (V7190) which gave a distribution that peaked around 0.5 μm.The use of polyether (PEG400 and PEG1000) led to a very large, whileuniform, distribution of particle size. The span of PLA domain sizedistibution in PEG1000 led is only 1.4, the smallest observed among thesamples as shown in Table 3.

TABLE 3 Modifier Type Vol. Weighted Mean/μm d (0.1)/μm d (0.5)/μm d(0.9)/μm Span PS 33.537 1.097 17.522 92.643 5.225 HEMA 2.5% 7.903 0.4080.997 10.009 9.632 HEMA 2.5% + SMA EF40 2.3% 24.787 0.634 5.319 65.04312.109 HEMA 2.5% + SMA EF80 2.3% 10.443 0.503 1.366 30.856 22.221 HEMA2.5% + Adipate 2.3% 5.408 0.773 2.823 12.056 3.997 HEMA 2.5% + Vikoflex7190 2.3% 1.784 0.295 0.642 2.235 3.023 HEMA 2.5% + PEG400 2.3% 9.5332.004 7.844 18.277 2.075 HEMA 2.5% + PEG1000 2.3% 34.114 15.489 31.03357.855 1.365

Example 3

Hydroxyl functional polystyrene was prepared in a batch reaction processby copolymerizing styrene with 2-hydroxyethyl methacrylate (HEMA) atvaried concentrations ranging from 0 to 5 wt. % in the feed (see Table4). The polymerization reaction was carried out in a CSTR-type batchreactor. Lupersol-233, available from Arkema, was added as the initiatorwith an initial concentration of about 170 ppm in the reaction mixture.The reaction was then run isothermally at 130° C. with continuousagitation at 150 rpm for about 3 hours or until 75% conversion wasobtained. The reaction mixture was then transferred onto an aluminum panand devolatized under active vacuum of less than 10 torr at 225° C. for45 minutes. The resulting material adhered to the aluminum surface ofthe aluminum pan.

TABLE 4 Feed Formulations in Batch Synthesis of HEMA-modifiedpolystyrene Run No. 0 1 2 3 4 Styrene 200 198 195 190 185.4 (grams) HEMA0 2 5 10 10.0 (grams) HEMA (%) 0.0 1.0 2.5 5.0 5.0 SMA EF-80 0 0 0 0 4.6(grams) TOTAL 200 200 200 200 200.00 (grams)

The solvent resistance was measured as the solvent intake relative tothe mass of polymer sample (of the same dimension), which was exposed toa particular solvent in a given time period (e.g., 30 min) at roomtemperature. The results in Table 5 demonstrate that HEMA-modifiedpolystyrene (2.5 wt. %) has a substantially lower solvent intake toward“oil” and thereby a higher resistance to the oil. The oil in thisexample is a 50/50 mixture of oleic acid and cottonseed oil. The solventresistance of HEMA copolymer toward protonated polar methanol was lowerthan the crystal polystyrene reference, and therefore, there was moremethanol intake to the HEMA copolymer than the crystal polystyrenereference.

TABLE 5 Solvent Intake Relative to Mass of Polymer Samples Oil MeOH(solvent) HEMA-modified Polystyrene 0.24 wt % 0.47 wt % Polystyrenereference 1.62 wt % 0.10 wt %

Sheets of hydroxyl polystyrene were prepared from samples containingvaried concentration of HEMA (0, 0.5, 1, 2.5 wt. %). Solvent intakeexperiments were conducted to generate a more detailed trend of solventresistance change as a function of HEMA concentration. The results inFIG. 4 show an increase of resistance toward the oil even with a minimaladdition of HEMA (0.5 wt. %). Marginal changes were observed withadditional HEMA incorporation (2.5 wt. %).

Polarity of HEMA-modified polystyrene was evaluated based on miscibilitywith PLA. As evident from FIG. 5, the size of the PLA phase inpolystyrene is strongly dependent on the amount of HEMA. With 5 wt % ofHEMA, the peak value of the PLA particle size was as low as 0.5 μm,while that for un-modified polystyrene was much larger. The PLA particlesize distribution was also more uniform.

Example 4

In a continued investigation on the effects of polar functionality onbiopolymer miscibility into polystyrene, polyethylene glycol (PEG) ofdifferent molecular weights and chemical form were studied. Twoapproaches were used to introduce PEG functionality into polystyrene,physically and chemically. In the first approach, PEG, at a loading ofabout 2 wt %, was added into the batch reactor as an additive, alongwith styrene monomer and HEMA co-monomer (in an amount of 2.5 wt. %). Asthe batch polymerization proceeded, PEG was incorporated into thepolystyrene matrix through physical, polar interactions with functionalgroups of the co-monomer along the polystyrene backbone. A PEG with anMn value of 400 g/mol and a PEG with an Mn value of 1000 g/mol were eachused as additives. In a second approach, PEG was incorporated into thepolystyrene backbone through copolymerization of styrene with amonofunctional methoxylated PEG methacrylate monomer (in an amount of 5wt %). Two such monomers were used, with PEG molecular weights of 350and 550 g/mol, respectively.

The structures of PEG functional compounds/co-monomers are illustratedbelow.

The plasticization effect of PEG can be seen from the decrease in theglass transition temperature as shown in Table 6 and FIG. 6. Furtherexamination of data reveals that the glass transition temperature (Tg)was slightly lower when the PEG having a higher molecular weight wasincorporated. It also appears that use of a PEG-functionalizedco-monomer was more effective at depressing the glass transitiontemperature than physical dispersion of PEG in HEMA-modifiedpolystyrene. The plasticization effect can also be observed from anincrease of melt flow in PEG functional polystyrene (see Table 6). Themelt flow after PEG modification doubled compared to the polystyrenereference, except for PEG-MA 350 where a substantially high Mz value(1.1 Million) and a relatively low melt flow (0.3) were observed. Also,a large increase of more than 100% in polydispersity (Mw/Mn) wasobserved for PEG-MA 350.

TABLE 6 Characterization of PEG Functional Polystyrene Modified Mn Mn MnMn MFI Tg Polystyrene (g · mol⁻¹) (g · mol⁻¹) (g · mol⁻¹) (g · mol⁻¹)Mw/Mn (g · 10 min⁻¹) (° C.) Polystyrene 129,000 269,000 408,000 260,0002.1 2.2 104.4 reference HEMA 2.5% 142,000 336,000 523,000 315,000 2.41.9~2.3 103.2 HEMA 2.5% + 120,000 261,000 405,000 247,000 2.2 4.7 87.6PEG400 HEMA 2.5% + 115,000 265,000 424,000 286,000 2.3 3.9 87.4 PEG1000PEG-MA 350 68,800 383,000 1,110,000 167,000 5.6 0.3 80.6 PEG-550 106,000334,000 681,000 242,000 3.2 4.4 79.6

PLA compatibility was evaluated by physically blending a modifiedpolystyrene sample with 5 wt % PLA 3251 in a mixer at 210° C. under anitrogen atmosphere for 3 minutes at 60 rpm. The PLA domain size inpolystyrene was characterized by dynamic light scattering in MEKutilizing a Malvern particle size analyzer and are shown in FIG. 7.Dynamic light scattering experiments show that the PLA blend withun-plasticized HEMA-modified polystyrene had a PLA domain size of about0.8 to 0.9 μm (peak value). The use of PEG-400 leads to a narrowerparticle size distribution but with a size one order of magnitude largerat about 8 to 9 μm. The use of the higher molecular weight PEG-1000continued to narrow the size distribution while driving up the size ofthe PLA domain to about 30 to 40 μm at peak. The PEG functionalco-monomer was not very effective at compatibilizing PLA. The PLA domainsize in the blends had a wide distribution from 2 to 100 μm.

Example 5

Batch reactions were run to incorporate varied amounts of 0, 1, 2.5 and5 wt % of caprolactone acrylate into polystyrene, according to theformulations shown in Table 8. The batch run conditions were the same asthose for HEMA-modified polystyrene in Example 1. With caprolactone inthe feed, the reaction appeared to drive up the viscosity significantlyat an early stage of the polymerization, particularly with 5 wt % ofcaprolactone in the feed. The resulting polystyrene had a strongtendency to climb the stir shaft and the reaction had to be stopped at aconversion of 50%. Similar phenomenon was observed with 2.5 wt %caprolactone acrylate but to a lesser extent. The reaction continued tofinish at 62% conversion. In contrast, no such reaction issues wereobserved with HEMA as the co-monomer.

TABLE 7 Feed Formulations in Batch Synthesis of Caprolactone FunctionalPolystyrene Run No. 1 2 3 4 Styrene (g) 200 198 195 190 Caprolactone (g)0 2 5 10 Caprolactone (wt %) 0.0% 1.0% 2.5% 5.0% TOTAL 200 200 200 200

The miscibility test with PLA was conducted with the results shown inFIG. 8. Compared to an un-modified polystyrene reference as well asHEMA-modified polystyrene, the caprolactone functional polystyrene showsperformance somewhere in the middle. While the compatibility ofpolystyrene with PLA increases with the addition of caprolactonefunctionality, the polar interaction seems to be less than that withHEMA at similar weight concentration.

As used herein, the term “biodegradable” refers to any composition thatis compostable or degrades from environmental heat, moisture, or fromthe action of naturally occurring microorganisms, such as bacteria,fungi, and algae.

As used herein, the term “bio-polymer” refers to polymers that arebio-derived, or otherwise produced by living organisms.

As used herein, the term “co-monomer” refers to a monomer which iscopolymerized with at least one different monomer in a copolymerizationreaction resulting in a copolymer.

As used herein, the terms “Continuous Stirred-Tank Reactor,” and“Continuously-Stirred Tank Reactor” and “CSTR,” refer to a tank whichhas a rotor which stirs reagents within the tank to ensure propermixing; a CSTR can be used for a variety of reactions and processes.

As used herein, the term “co-polymer,” also known as a “heteropolymer,”is a polymer resulting from polymerization of two or more monomerspecies.

As used herein, the term “copolymerization” refers to the simultaneouspolymerization of two or more monomer species.

As used herein, the term “homopolymer” refers to a polymer resultingfrom polymerization of a single monomer species.

As used herein, the term “monomer” refers to a relatively simplecompound, usually containing carbon and of low molecular weight, whichcan react by combining one or more similar compounds with itself toproduce a polymer.

As used herein, the term “polymer” generally includes, but is notlimited to homopolymers, co-polymers, such as, for example, block,graft, random and alternating copolymers, and combinations andmodifications thereof.

As used herein, the term “polar functional group” generally refers to agroup of atoms within or attached to a molecule that exhibits a degreeof polarity or imparts a degree of polar functionality to the molecule.

It is to be understood that while illustrative embodiments have beendepicted and described, modifications thereof can be made by one skilledin the art without departing from the spirit and scope of thedisclosure. Where numerical ranges or limitations are expressly stated,such express ranges or limitations should be understood to includeiterative ranges or limitations of like magnitude falling within theexpressly stated ranges or limitations (e.g., from about 1 to about 10includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13,etc.).

Use of the term “optionally” with respect to any element of a claim isintended to mean that the subject element is required, or alternatively,is not required. Both alternatives are intended to be within the scopeof the claim. Use of broader terms such as comprises, includes, having,etc. should be understood to provide support for narrower terms such asconsisting of, consisting essentially of, comprised substantially of,etc.

While the foregoing is directed to embodiments, versions and examples ofthe presently disclosed composition, which are included to enable aperson of ordinary skill in the art to make and use when the informationin this patent is combined with available information and technology,the embodiments are not limited to only these particular embodiments,versions and examples. Also, it is within the scope of this disclosurethat the embodiments disclosed herein are usable and combinable withevery other embodiment disclosed herein, and consequently, thisdisclosure is enabling for any and all combinations of the embodimentsdisclosed herein.

What is claimed is:
 1. A styrenic composition comprising: a polarmodified styrenic co-polymer resulting from the polymerization of acombined mixture of at least one styrenic monomer and at least onecomonomer; a biodegradable component comprising polylactic acid; and apolar additive, wherein the polar additive is polyether, wherein the atleast one comonomer comprises a polar functional group, the at least onecomonomer selected from the group consisting ofcaprolactone(meth)acrylate, polyethylene glycol(meth)acrylate,silyl-(meth)acrylate, and fluoro-alkyl(meth)acrylate; wherein the polarmodified styrenic co-polymer and the biodegradable component arecombined to obtain a styrenic composition comprising the biodegradablecomponent.
 2. The composition of claim 1, wherein the polar additive ispresent in the styrenic composition in amounts ranging from 0.5 to 10 wt% based on the total weight of the styrenic composition.
 3. Thecomposition of claim 1, wherein the polar modified styrenic co-polymeris present in amounts ranging from 75 to 99 wt % based on the totalweight of the styrenic composition.
 4. The composition of claim 1,wherein the biodegradable component in the styrenic composition has aparticle size distribution having a peak particle size of less than 2.0μm.
 5. The composition of claim 1, wherein the styrenic compositioncomprising the biodegradable component exhibits a polydispersity indexranging from 1.0 to 5.0.
 6. The composition of claim 1, wherein thestyrenic composition comprising the biodegradable component exhibits amelt flow index of at least 1.0 g/10 min., as determined in accordancewith ASTM D-1238.
 7. The composition of claim 1, wherein the styreniccomposition comprising the biodegradable component exhibits a glasstransition temperature ranging from 50 to 200° C.
 8. The composition ofclaim 1, wherein the styrenic composition comprising the biodegradablecomponent has an average particle size distribution ranging from 0.1 to1000.
 9. The composition of claim 1, wherein the styrenic compositioncomprising the biodegradable component has a particle size distributionhaving a peak particle size ranging from 30 to 300 μm.
 10. Thecomposition of claim 1, wherein the styrenic composition comprising thebiodegradable component has a particle size distribution having a peakparticle size ranging from 0.3 to 3 μm.
 11. The composition of claim 1,wherein the styrenic composition comprising the biodegradable componenthas a particle size distribution having a peak particle size rangingfrom 2 to 10 μm.
 12. The composition of claim 1, wherein the styreniccomposition comprising the biodegradable component has an averageparticle size ranging from 0.3 to 30 μm.
 13. The composition of claim 1,wherein the polar additive comprises polyethylene glycol.
 14. Thecomposition of claim 1, wherein the polar modified styrenic co-polymeris present in amounts ranging from 92 to 99 wt % based on the totalweight of the styrenic polymer.
 15. The composition of claim 1, whereinthe polylactic acid is present in amounts ranging from 0.1 to 8 wt %based on the total weight of the styrenic polymer.
 16. An article madefrom the composition of claim
 1. 17. A method of making a styrenicpolymer comprising a biodegradable component comprising: combining astyrenic monomer and a comonomer comprising a polar functional group toform a combined mixture, the comonomer comprising a polar functionalgroup selected from the group consisting of caprolactone(meth)acrylate,polyethylene glycol(meth)acrylate, silyl-(meth)acrylate, andfluoro-alkyl(meth)acrylate; subjecting the combined mixture topolymerization to obtain a polar modified styrenic co-polymer; andcombining the polar modified styrenic co-polymer with a biodegradablecomponent and a polar additive to obtain the styrenic polymer comprisingthe biodegradable component, wherein the biodegradable componentcomprises polylactic acid, and wherein the polar additive comprisesstyrene maleic anhydride, glyceride oil, polyether, polyester, orcombinations thereof.
 18. The method of claim 17, wherein thebiodegradable component in the styrenic composition has a particle sizedistribution having a peak particle size of less than 2.0 μm.